Alkylation of aromatic hydrocarbons



Patented Oct. '24, 1944 ALKYLATION OF AROMATIC HYDBOCARBON S Louis Schmerling and Vladimir N. l'patiefl, Chicago, Ill., assignors to Universal Oil Products Company, Chicago, 111., a corporation of Delaware No Drawing. Application June 16, 1941,

Serial No. 398,233

6 Claims. (CL 260-671) Thi invention relates to the production of .alkyl aromatic compounds and more particularly to the production of alkylated aromatic hydrocarbons from aromatic hydrocarbons and naphthenic hydrocarbons.

Various methods have been proposed for the alkylation of aromatic hydrocarbons. These prior processes have mainly involved reacting aromatic and olefinic hydrocarbons. However, it has also been proposed to alkylate aromatic hydrocarbons with naphthenic hydrocarbons at low temperatures of up to about 120 C. in the presence of aluminum chloride or zirconium chloride. A disadvantage of these Processes catalyzed by a metal halide is that the consumption of catalyst is relatively high and may be prohibitive from a commercial point of view when the fact is taken into consideration that spent catalyst of this type is generally not readily recovered.

In one specific embodiment the present invention comprises the manufacture of alkyl derivatives of aromatic hydrocarbons by treating aromatic hydrocarbons with naphthenic hydrocarbons in the presence of a zinc chloride-containing catalyst at"a temperatur of from about 200 to about 450 C.

The alkyl aromatic hydrocarbons thus formed may be used for increasing the antiknock value of gasoline motor fuels by blending, or they may be utilized in the preparation of pure alkylated aromatic hydrocarbons.

Aromatic hydrocarbons which are alkylated according to the process of this invention include benzene, toluene, other partially alkylated benzenes, naphthalene, partially alkylated naphthalenes, other poly-nuclear aromatic hydrocarbons, etC., which are obtainable by the distillation of coal, by the dehydrogenation of naphthenes, or by the dehydrogenation and cyclization of aliphatic hydrocarbons or of alkylated aromatic hydrocarbons.

Naphthenic hydrocarbons which are reacted with aromatic hydrocarbons according to the process of this invention include cycloparaflins and alkyl cycloparafilns with 5- and 6-carbon atom rings, particularly cyclopentane, cyclohexane, and a number of the corresponding alkylated cyclopentanes and alkylated cyclohexanes. Th difierent alkylating naphthenic hydrocarbons which are thus utilizable will not necessarily be employed under the same condition of operation within the limits hereinafter set forth.

The preferred catalyst for use in efiecting the process of the present invention is a composite of zinc chloride and a carrier, preferably alumina or a material containing a substantial proportion of alumina as clays, silica-alumina composites, bauxite, etc. Diatomaceous earth and silica are also utilizable as supporting material for zinc chloride.

The proportions of carrier and zinc chloride may be varied as desired to make catalyst composites of different activities. found possible and practical to make stable granular catalysts resistant to disintegrating innuences by using from about 5 to about 50% by weight of zinc chloride and from about to about 50% by weight of activated alumina or an alumina-containing carrier. These materials in finely powdered form, after thorough mechanical mixing, maybe subjected to drying, pelleting, I

gen and/or of hydrogen chloride. There is little or no carbon formation upon the catalyst when alkylations are carried out under hydrogen pressure but carbon formation does occur to a substantial extent in the absence of hydrogen. Hydrogen chloride introduced to the reaction mixture appears to exert a promoting effect upon the zinc chloride-containing catalyst.

In effecting reaction between aromatic and naphthenic hydrocarbons according to the process of the present invention, the exact method of procedure will vary with the nature of the reacting constituents, their relative proportions, the activity of the catalyst employed, and other factors. A simple procedure utilizable in the case of an aromatic hydrocarbon which is normally liquid under the operating conditions consists in contacting said aromatic hydrocarbon with a naphthenic hydrocarbon or naphthenic hydrogen fraction in the presence of a zinc chloridecontaining catalyst at a temperature of from about 200 to about 450 C. under a pressure of from substantially atmospheric to approximately 200 atmospheres. Intimate contact of the reacting components with the catalyst is effected by passing the reaction mixture through a fixed bed of the granular catalyst containing zinc chloride or the reacting components may be Thus it has been mixed with flnely divided catalyst and the resultant mixture or slurry may then be passed through suitable reactors such as heated tubular members. The hydrocarbon mixture subjected to alkylationt rea tment preferablyicontains,a inolar excess: 6: aromatic jhydrocarbomrelative; to naphthenic hydrocarbon in order to eflfect the production of a relatively high' yield of alkylated r omatic hydrocarbons.

While methods of passing m eif6r-iiatr; na; naphthenic hydrocarbons, either togetheror countercurrently, through asuitable reactor taining the ranula at y ti eicus amarii P19 cedure, the condensation or :i alkylationmreaction may be eflfected in a closed vessel in which some of the reacting constituents and products are in liquid phase and in which the,catalyst' prefer ably in finely divided form and is maintained 'in for the same purpose, but under other operating dispersion or suspension by some method-of agis.

z-tation. I The choice of. operating procedureis dependent uponth circumstancssuch astem'pe'raur pre e: -.I 'i i d to e met f e t e o producing the. desired; reaction between (particular aromatic and'naphthenic hydrocarbons. f

' 7 Reactions bettiieenfv arcr'natic and. naphtheni'c hydrocarbons in the presence 'ofsupported zinc chlorideapparently involve the breaking of the cycloparailinring with the iorniation of jalkyl radicals or which undergo further jreactionwith thefaromatic hydrocarbons or aromatic hydrocarbons present to form the .alkylated and more-highly aromatic hydrocarbons; Thus he ne and cyclohexane interact toform toluene,

. et 1 benzene, xylenes, andlvhigher al- 1 kylated benzenes. Poly-alkylated aromatic hy-' drocarbons areformed when a mono-alkylated aromatic hydrocarbonorigin'ally charged undergoes further reaction with a naphthenic hydrocarbon or iragmentformed by decomposition of a naphthenic hydlrocarbon} since the reactions of an aromatic hydrocarbon with anaphthenic hydrocarbon in the presence of azinc chloridecontainingcatalystare notunderstoodclearly or completely,jthe above mechanistic concept should not be misoonstrued to limit thegenerally broad Scope einve ion- The process thus utilizesfcycloparamnic hydrobons and-hydrocarbon mixtures containing naphthenes maybeemployed as alkylating agents instead of the more-reactiveolefinic hydrocarbons. For example, instead of utilizing only the oleflns present in cracked hydrocarbon mixtures and 4 mm a a ic h c r ons, oleflns normally constituting only minor percentages of 1 "such cracked products) naturally. occurring naphthenie hydrocarbons or naphthenic hydro carbon fractions may be usedwhich contain no oleflns. Inlthe, case "of hydrocarbon products containing cleflns which may be derived by crackn: naphthenes, the oleflns. may be removed by absorption in acid, byfpolymeriaatiomcr by more generally known 'alkylatidn reactions, and the residual hydrocarbons. may then bev employed to alkylate further amounts "of aromatic hydrocarbonsin the presence of a zincchlorideicontaining catalyst by methods hereinabove indicated.

Acomposite of zincchloride on a carrier is a preferred for the} present process as it I permits continuous falkylation' of aromatics with naphthenesfin the presence of a fixed, catalyst A zinc chloride-carrier composite alsoihas the advantage over aluminum chloride utilized" conditions, in that the zinc chloride contained in the composite does not form addition compounds or complexes with aromatic hydrocarbons. Thus while, chloride,:;forms --sludge-like mafial commonly referred to" as lowrejlayer com-- pounds, a zinc chloridecatalyst remains relatively cleanand active for a relatively long period of time particularly when charging hydrogen and with additional quantities of the naphthenic and 20.

aromatic hydrocarbons being charged to contact witiiithej 'zlnc hlori e-c taining catalyst; The total' alkylatedj product "thus freed lfrom the excessfof the 'ori'ginally'charged aromatic hydro- 'carbon is separated into desired fractions by. discate'diare shown in termsof the proportions of tillation at ordinary or reduced pressure'o'r by other suitable, means.

The catalyst compositions he'reinabcve indithe mat'erials irom'which the catalyst composites are generally prepared rather than the. exact proportions or the. catalyst composites themselves as these may be, somewhat diflerent due, to formation of some zinchydroxychloride, zinc oxychloride,for other material resulting from hydrolysis or partial hydrolysis oia portion of zinc chloride or to other conversions. which are not clearly understood.

' The followingfexample is given to illustrate carbons to. combineiwith andalkylatearomatic hydrocarbons. The practical utilityoi the process appears in that various naphthenic hydrocar 'of 1267, atmospheres.

the character or results obtained by the useof the present process, although the data presented are only from'a selected case and are not introducedwith the intention. of unduly restricting the generally broad'scope offtheinventionh by weight ofbenzene, 52 parts by weight oicyclo -hexane, 2 parts by. weight of hydrogen chloride, and 15 parts by weight of a composite formed from by weight of zinc chloride and by weight of alumina, were charged to a rotating autoclave,"hydrogen"was intr'txiuced thereto vto 1100' atmospheres: initial pressure, and the autoclave so charged was heated 4 hoursat 400 C. under a pressure v v After the autoclave had cooled, the reaction products removed therefrom consisted of 113 parts by weight or liquid hydro- V carbons, 16 parts by weight of gray-colored catalyst,and 6 parts byflweight of a gaseous hydrocarbon fraction containing 21.4% by volume of propane, 32.6% isobu'tane, 15.4% normal butane, 30.6% of pentane and higher hydrocarbons. Fractional distillation of. the 113 parts by weight of liquid hydrocarbons separated this material into 27% byvvolume' boiling. below 78 0.. 55%

boilingibetween '78 and 86 ,C., 7% boiling betwee and' 0., 3% between 105 andf C.,4% between 125 and .C., and 4% of distillation residue. The difierent fractions boiling abovethe recovered benzene contained substan 't ial amounts of toluene, xylenes, ethyl benzene,

and higherboiling alkylated benzenes.

The novelty and utility. of the process of the presentiinvention are evident from they preceding specification and examples given, although neither section intended to unduly limit its generally broad scope.

I We claim as our invention: 1. A process for producing substantial yields of alkylated aromatic hydrocarbons which com prises contacting an aromatic hydrocarbon with i a naphthenic hydrocarbon at a temperature of from about 200 to about 450 C. in the presence of a catalyst comprising zinc chloride, zinc oxychloride and zinc hydroxychloride.

2. A process for producing substantial yields of alkylated aromatic hydrocarbons which comprises contacting an aromatic hydrocarbon with a naphthenic hydrocarbon and hydrogen at a temperature of from about 200 to about 450 C. under a pressure of from substantially atmospheric to approximately 200 atmospheres in the presence of a catalyst comprising zinc chloride, zinc oxychloride and zinc hydroxychloride.

3. A process for producing substantial yields of alkylated aromatic hydrocarbons which comprises contacting an aromatic hydrocarbon with a naphthenic hydrocarbon at atemperature of from about 200 to about 450 C. under a pressure of from substantially atmospheric to approximately 200 atmospheres in the presence of hydrogen chloride and of a catalyst comprising zinc chloride, zinc oxychioride and zinc hydro'xychloride.

4. A process for producing substantial yields of alkylated aromatic hydrocarbons which comprises contacting an aromatic hydrocarbon with a naphthenic hydrocarbon and hydrogen at a temperature of from about 200 to about 450 C. under a pressure of from substantially atmospheric to approximately 200 atmospheres in the presence of hydrogen chloride and of a catalyst comprising zinc chloride, zinc oxychloride and zinc hydroxychloride.

5. A process for producing substantial yields of alkylated aromatic hydrocarbons which comprises contacting an aromatic hydrocarbon with a naphthenic hydrocarbon at a temperature of from about 200 to about 450 C. in the presence of a composite comprising essentially zinc chloride, zinc oxychloride, zinc hydroxychloride and;

an aluminum oxide-containing carrier.

6. A process for producing substantial yields of alkylated benzenes which comprises contacting benzene with a naphthenic hydrocarbon at a temperature of from about 200 to about 450 C. under a pressure of from substantially atmospheric to approximately 200 atmospheres in the presence of a catalyst comprising zinc chloride, zinc oxychloride and zinc hydroxychloride.

hours VSCHMERIJNG. VLADIMIR N. IPATIEFF. 

